Valves, which are used to control the flow of liquids in conduits, are known to degrade with time by wear and ageing. More specifically gate valves have a body, a hand wheel for closing or opening the valve by means of a stem provided with a first end connected to the hand wheel and a second end connected to a disc for obturating the valve, and several components placed together around and along the stem. These components include, starting from the one of the components that is closest to the hand wheel, a gland flange, a gland, a packing, a packing box and a packing ring. The packing ring is squeezed between a shouldering of the stem and the packing box. The packing ring which is for preventing leaks has to be changed regularly.
Traditionally, to change the packing ring on a gate valve, one has to shut down the flow of liquid in the conduits before and after the valve, drain the liquid from the valve and surrounding conduits, remove the gate valve from the surrounding conduits and send it from the workplace to a maintenance workshop where the valve is disassembled and verified. When the valve is in good order, it is sent back to the workplace where it is connected to the conduits. Then the flow of liquid is re-established before and after the valve.
It is an object of the present invention to provide a maintenance method and a maintenance kit for a gate valve, allowing a maintenance thereof that is faster than the one of the prior art.
It is another object of the present invention to provide a maintenance method and a maintenance kit for a gate valve, allowing a maintenance thereof that is less expensive than the one of the prior art.
It is another object of the present invention to provide a maintenance method and a maintenance kit for a gate valve, allowing a maintenance of the gate valve without a removal thereof from the surrounding conduits.